interface Ibird {
  fly: () => void
}

interface Ifish {
  swim: () => void
}

interface IFlyfish extends Ibird, Ifish {
  name: string
}

let ff: IFlyfish = {
  fly() {
    console.log('我会飞');
  },
  swim() {
    console.log('我会游泳');
  },
  name: '我是飞鱼'
}

console.log(ff);